| 1 | We can deaden the noise of the room with thick walls. | |
| 2 | Whatever happened to a big, solid, soundproof door? | |
| 3 | No sound comes from the shell, though there is plenty of air in the room. | |
| 4 | Over to the soundproof booth, where Dr.Resnick has me strap on some form-fitting headphones.The room is still and quiet. | |
| 5 | Wing feather with serrated edge, muffles sound, Courtesy Peter Mullen, Ph.D. |